Architecture for when money is on the line.
I review architecture, assess technical risk, help teams hire, and advise engineering leads.
I'm Kalle Ott, a Berlin-based Staff Software Engineer at a global crypto exchange and former Head of Engineering at Timeless Investments.
$2 → $0.08KYC license cost per verified user at Timeless Investments: from about $2 to about $0.08.
After replacing Onfido with self-hosted FaceTec.See the KYC stack in the archive
1919
20+20+
44
Shipped foras an employee or agency developer
Services
What you can hire me for.
For founders, engineering leaders, and investors in fintech and other high-stakes products.
Fixed price
Architecture review
Before a rewrite, platform switch, or scaling push, I review your code and architecture.
You getPrioritized recommendations and a working session with your leads to agree next steps
Fixed price
Technical due diligence
For investors and acquirers assessing a mobile or web product. At Timeless, I prepared the engineering side of investor technical due diligence.
You getWritten findings on architecture, code quality, and technical risks, with recommended next steps
Fixed price or retainer
Hiring and career ladders
Interview loops and career ladders, modeled on the ones I built for the Timeless engineering team.
You getAn interview process, a career ladder, or both, as agreed in scope
Monthly retainer
Engineering advisory
Regular working sessions with your CTO or engineering lead on architecture, delivery, and team decisions.
You getWorking sessions and a written decision log
- Availability
- A few hours a week or a fixed-scope engagement, alongside my full-time role. Remote, in English or German, from Berlin (CET/CEST).
- Conflicts
- Cleared with my employer; no direct competitors. Tell me your company up front and I’ll flag any conflict.
- Confidentiality
- Happy to sign an NDA. Before work starts, we agree which tools may access your code and confidential material.
Experience
The roles behind the advice.
Selected roles; implementation details are in the project archive.
Browse the project archive- Global crypto exchange
Staff Software Engineer
I own the React Native architecture and developer experience behind the iOS and Android apps that 20+ app engineers build on, in an org of 800+ engineers.
20+ app engineers
Current
- Timeless Investments
Head of Engineering
Replaced Onfido with self-hosted FaceTec, cutting KYC license cost from about $2 to $0.08 per verified user.
KYC project$0.08 per verified user, down from about $2
Verified
- Timeless Investments
Prepared the engineering side of investor due diligence, and built the team, its interview process, and its career ladder.
4 years as Head of Engineering
DD ready
- Timeless Investments
Led the iOS and Android app from first build to the stores, and built its design system with the design team.
View the app on the App Store (opens in a new tab)iOS and Android apps
Shipped
- About You
Senior Frontend Engineer
Worked on the desktop shop redesign, moved a large React codebase to function components and hooks, and built a unified tracking SDK that enforced standard events across the shop.
Visit aboutyou.de (opens in a new tab)Earlier
How we’d work together
From first call to clear next steps.
AI-first. Human-reviewed.
Listen
A free 30-min intro call about your product, team, and constraints, and a straight answer on whether I’m the right fit.
Scope
A short written scope with objectives, format, price, and success criteria.
Review and advise
I review the agreed material, document findings, and work through decisions with your team. Where implementation is in scope, coding agents assist and I review every change.
Hand off
A written record of decisions and next steps, so your team carries on without me. Where it helps, I hand over the coding-agent configuration too.
Expertise
Mobile-first, with the full stack behind it.
- Fintech
- Identity verification (KYC), in-app payments, and preparing for investor technical due diligence.
- Mobile
- Architecture, release pipelines, and performance for growing iOS and Android teams.
- Web
- React and Next.js architecture, accessibility, and design systems.
- Platform
- Backend and infrastructure choices that fit your team’s size, from Node.js services to Kubernetes.
- Delivery
- Code review, CI/CD, and release practices that keep changes small and releases frequent.
- Agent workflows
- Coding-agent setups with the reviews, evals, and guardrails engineers need to trust them.
Get in touch
Where does your product or team need help?
Tell me what you’re working on. I’ll check fit and conflicts before we scope the work.